The present invention broadly relates to roll or calendering devices and, more specifically, pertains to a new and improved construction of a two-roll calender with heated calender rolls.
In its more specific aspects the roll or calendering device of the present invention relates to a two-roll calender having heated rolls for the pressure and thermal treatment of webs or sheet materials of plastic or textile or both, such as fiber webs.
In heretofore known two-roll calenders of this type the heated rolls are exposed to room or ambient temperature without heat or thermal insulation which leads to significant energy losses. These energy losses have the advantage, as far as they are uniform, that they have an equalizing effect on the temperature profile of the rolls and therefore guarantee a uniform quality of the sheet materials or webs produced, particularly with respect to their width. If the above-mentioned heat losses are prevented the required uniformity of the temperature profile over the length of the roll is no longer guaranteed.